This invention relates to an assay method for hepatitis A antibody and antigen, and to plasma and gamma globulin of known hepatitis A antibody titer. More particularly it relates to an immune adherence assay method and to the use of such method to detect plasma and prepare gamma globulin having a known protective titer of hepatitis A antibody.
Hepatitis A is a liver disease which, while not commonly fatal, can involve many weeks of debilitating illness. It is usually spread by direct contact with an infected individual or by contaminated drinking water or food. Presently known methods for the detection of hepatitis A antigen or antibody lack sensitivity, are time-consuming and expensive. There has not been heretofore a sensitive test which is both specific and reproducible for quickly determining whether or not the sera from a patient or a donor contains hepatitis A associated antibody or antigen. For example, the prior art method for determination of hepatitis A antibody involves neutralization tests in marmoset monkeys. This method takes from 8 to 10 weeks and only permits evaluation of 1 or 2 samples per 100 marmosets.
The present method of treating an individual believed to be in danger of contracting hepatitis A is to administer gamma globulin. The rationale for this treatment is the expectation that the gamma globulin contains hepatitis A antibody in a quantity sufficient to confer immunity to the exposed individual. It is well known, however, that gamma globulin fails to confer immunity to certain exposed individuals.